Amebiasis is a deadly parasitic infectious disease. We propose to re-examine the epidemiology of amebiasis in Turkey using modern diagnostic tests and also test for genetic differences between strains of Entameoba histolytica that cause asymptomatic infection, colitis and liver abscess. In Specific Aim 1, we will determine the prevalence of amebiasis in Van, a city in the east region of Turkey using diagnostic techniques (antigen detection based-ELISA test and amebic-specific PCR) on stool samples of patients with diarrhea, dysentery and stool samples from asymptomatic individuals. We hypothesize that E. histolytica is a more frequent cause of diarrhea and dysentery in Van than has been determined by stool "ova and parasite" exams. A more accurate estimate of the burden of disease due to amebiasis is important for design of treatment and prevention strategies. After diagnosis of patients with intestinal amebiasis and liver abscess, we will test if genetic differences exist between liver abscess and intestinal isolates of E. histolytica in Specific Aim 2. Genetic diversity will be determined by 1) nested PCR amplification and sequencing of the CRD region of the lectin gene, 2) nested PCR -SREHP gene and 3) DNA microarray analysis. This project will be carried out at the Gulhane Military Medical Academy, Turkey, in collaboration with the University of Virginia. This proposal study is an extension of NIH grant #R01 Al 26649-12.